Docker Interview Questions and Answer Part – 28

What is a tag?

• A reference to a registry
• A reference to a repository
• A reference to a specific image in a repository (Ans)
• A reference to a specific image in a registry

Why are image layers read only?

• So they can be compressed to reduce disk space
• So we cannot write data inside a container
• So they can be reused (Ans)

Which of the following container types doesn’t use namespace isolation?

• Windows Server Container
• Hyper-V Container (Ans)
• Linux Container

Which of the following provides the initial container file system?

• Volume(s)
• Network drive
• Host file system
• Image (Ans)

Database data should be stored in:

• Image layer
• Volume (Ans)
• Container Read/Write layer

In the past, to find software, we often used standalone web sites hosted by the creator of the software. Now, with Docker, how do we discover software?

• Package Managers
• Still use standalone web sites
• Docker Engine
• App Stores
• Docker Hub (Ans)

In the past, we usually downloaded software in some sort of package to install it, for example a zip file or MSI file. Now, with Docker, how do we download
software?

• docker pull (Ans)
• docker start
• docker ps
• docker download

When executing the command “docker pull microsoft/aspnet:4.6.2” what is the “microsoft” piece called?

• User (Ans)
• Image
• Tag
• Registry
• Repository

On a computer, with either Linux or Windows installed, there’s a program that runs in a privileged mode that abstracts hardware and provides services to other
processes. What is this program?

• User
• User space
• Kernel
• Kernel space (Ans)
• Application

After stopping a container, how do you run the application in it again?

• docker run
• docker start (Ans)
• docker pull
• docker restart

What’s the primary purpose of docker-compose?

• Build containers, volumes, and networks (Ans)
• Build images
• Pull and push images
• Cleanup containers.
• Build containers

What does the -d in docker run -d nginx do?

• Runs an attached container
• Runs a container that will display output from the NGINX process in our console
• Deletes the container when we stop the NGINX proces
• Runs a detached container (Ans)

Where does the file system come from for a container?

• From the machine the container is started on
• From the image used to create the container (Ans)
• From another special container called a parent container
• From a remote network share hosted through Hyper-V

Which of the following allows you to share the host file system with a process in a container?

• Network drive(s)
• Image(s)
• symlinks
• Volume(s) (Ans)

How can you see the output of a process running in a detached container?

• docker output
• docker Is
• docker run -it
• docker exec -it
• docker logs (Ans)

What does docker commit do?

• Copies files into a container
• Creates a container
• Duplicates a container
• Creates a snapshot of a running container for rolling back
• Creates an image (Ans)

Which of the following is a good analogy for creating a container?

• Installing software (Ans)
• Downloading software
• Extracting a zip file
• Running software

How can processes in different containers talk to each other when using docker-compose?

• Embedded DNS for Service Discovery (Ans)
• Pass IP addresses in configuration files
• Pass IP addresses in environment variables
• Linking containers

What does an image contain?

• The user space files (Ans)
• Only an application’s files
• Both the user and kernel space files
• The kernel space files
• The operating system

Removing an image is akin to what in traditional software management?

• Deleting an installer file or zip file (Ans)
• Uninstalling an application
• Restarting an application
• Stopping an application

Rajesh Kumar

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